Photogrammetric Capabilities of the Kodak DC40, DCS420 and DCS460 Digital Cameras

The aim of this study is to assess the impact of sensor size and resolution of different digital camera sensors upon the accuracy and precision of three dimensional data derived by photogrammetry. Kodak DC40, DCS420 and DCS460 digital cameras were used to produce digital images of retroreflective targets in a 4 m three dimensional test field. The image locations of the targeted points were automatically measured using an off the shelf image processing software package. Two different sub-pixel measurement approaches were examined: centre of gravity and weighted mean. From the automated sub-pixel measurement of the targeted points, results indicate that the high resolution DCS460 camera produces optimum results using either the weighted mean or centre of gravity approaches. Although this was perhaps expected, the far lower resolution DC40 camera performed better than was originally anticipated, suggesting potential for the cheaper DC40 for many applications.     

Measuring Flume Surfaces for Hydraulics Research Using a Kodak DCS460

A critical problem in hydraulics research is accurate measurement of fluvially worked sediments, both in the field and in scaled representations of field situations in laboratory flumes. Such measurement must provide information on individual grain characteristics, and their organisation into structures referred to as bedforms. Existing measurement approaches are based upon mechanical or laser profiling devices, which are both expensive and take considerable time to acquire data, particularly where information is required at very high densities. This paper demonstrates how conventional automated terrain model extraction software, combined with image acquisition using a Kodak DCS460 digital camera, has been effective in generating digital elevation models of complex bed morphology. This has reduced time spent collecting data in the flume and has allowed data collection at much higher spatial and temporal densities. Application of the method is illustrated by research carried out at Hydraulics Research Wallingford. Issues discussed include configuration of photographs and control coordinates; appropriate camera calibration methods; stability of inner orientation of the Kodak DCS460; and accuracies obtained. Comparisons with independent check data reveal that accuracies of ±2.5mm have been achieved using a camera-to-object distance of 4.2 m.     

Principal Point Behaviour and Calibration Parameter Models for Kodak DCS Cameras

Digital still cameras have been widely adopted for close range photogrammetry and machine vision applications. Due to the advantages of onboard storage of digital images, portability and rapid data processing, digital still cameras are rapidly becoming standard equipment for measurement tasks such as industrial metrology and heritage recording. As for any metric application, the accuracy of the derived object data is dependent, amongst many other factors, on the accuracy of the camera calibration. For the vast majority of photogrammetric applications, use of the simple case of a block invariant calibration model comprising the primary physical parameters, including the principal point position, is sufficient. However, cameras designed for photojournalism and domestic use, such as the Kodak DCS420 and 460 cameras, are well known for their calibration instability because the design is based on a 35 mm SLR camera body. In particular, previous research has shown that the principal point location is prone to movement during normal handling of the camera, due to the mounting mechanism of the CCD array. This paper reports on an investigation of the physical behaviour of the principal point location and compares different calibration parameter models for the Kodak DCS420 and DCS460 digital still cameras.     

Geometric assessment of the kodak DCS Pro back

This paper reports on an investigation into the suitability of the Kodak DCS Pro Back for use in close range photogrammetric measurement. The camera back, being used in conjunction with a medium-format non-metric camera, has been assessed with a view to using it for low- to medium-order photogrammetric work in architectural recording. Examinations centred upon the stability of the camera back with respect to the camera body and the effects of the removable infrared filter that is present immediately above the camera's focal plane. Ultimately the camera combination was deemed suitable for application in recording of this kind and is now in active use by the Metric Survey Team at English Heritage.     

Multiplotting With Images from the Kodak DCS420 Digital Camera

This paper explores the potential of a digital camera to produce multiple images suitable for plotting. The objective was to build a three dimensional database by linking triangulated images from a Kodak DCS420 digital camera with a computer aided measurement system. The system then supplied X, Y, Z data from x, y image co-ordinates captured off two or more images. Relative accuracy in object space was around 1;50 000.     

Aerial Photography for Survey Purposes with a High Resolution, Small Format, Digital Camera

This paper discusses the work carried out to obtain stereoscopic "photography" from airborne platforms with a Kodak DCS200 digital camera, as part of an investigation into the suitability of current digital camera technology for use in air survey. Details of the work, from the initial test flight in a Cessna light aircraft through to tests utilizing a Thruster microlight platform, are documented. The paper concludes with a summary of the present shortcomings in obtaining aerial photography for survey purposes with still video technology and discusses the future prospects.     

基于DLT方法的非量测数码相机检校研究

普通数码相机在图像获取方面有着很多优势,但它是非量测化相机,不能用普通数字摄影测量方法对其数字图像进行处理。针对这一情况,本文提出了建立3维控制场对非量测数码相机进行检校,采用DLT（直接线性变换）方法计算出非量测数码相机的内外方位元素,实现非量测数码相机获取像对的可量测化。最后通过在黑龙江省地理信息产业园主楼区域建立3维控制场的试验,进行数据采集后获取了实际的3维模型。     

室内控制场数码相机检校应用于通用航空摄影测量的可行性研究

非量测数码相机已广泛应用于计算机视觉、摄影测量等领域,但必须对其进行内定向和构像畸变的校正。常用的检校方法主要有室外检校法和室内检校法两类,其中利用室外三维控制场进行数码相机检校是目前较为成熟的做法,而室内三维控制场检校精度能否达到常规比例尺航空摄影要求尚未进行有效验证。通过论述一整套室内三维控制场相机检校方法,并对比分析两种检校结果表明,室内三维控制场检校精度还无法满足通用航摄精度要求。     

非量测CCD数码相机的航空摄影测量应用

研究非量测CCD数码相机应用于航空摄影测量的技术方法.采用基于自检校光束法平差严格标定非量测CCD数码相机;提出基于相对定向、三视张量、自由光束法平差、区域网光束法平差的空中三角测量流程.实验表明,严格标定的数码相机,可以应用于大比例尺航空摄影测量.     

非量测数字相机实验室几何标定

非量测数字相机的几何标定,包括内方位元素和畸变的精确测定,直接影响其用于航空摄影测量的最终精度。本文研制出一套非量测数字相机实验室几何标定系统。该系统采用平行光管加星点板作为目标发生器,在测量出一组目标点在相机的CCD靶面上的像点坐标及对应的平行光线的入射角后,结合几何标定的数学模型,可以实现相机的高精度几何标定。采用佳能EOS 5D MarkⅡ和哈苏H3D两款典型的数字相机进行了试验与分析。试验结果验证了本文标定方法的正确性以及精度的可靠性。     

轻小型组合宽角低空相机检校技术研究

轻小型组合宽角低空相机由四个非量测的CCD面阵相机组合而成,其内方位元素未知,并且相机畸变差较大.而无人机航空摄影测量作业对CCD相机的光学畸变参数有较高的要求,因为参数的一个像素的误差常常会导致地面几米甚至数十米的误差,因此对组合相机进行高精度检校是无人机航空摄影测量作业的关键步骤.本文采用多片空间后方交会方法在室外...     

High Resolution Still Video Camera for Industrial Photogrammetry

Still video cameras are easy to handle, portable, digital image acquisition devices for close range photogrammetry. They allow fast object recording without being connected to a computer. As an example of the new camera type, the high resolution Kodak DCS200 is presented in this paper, combined with the DPA digital photogrammetric station used for image measurement and object reconstruction. The performance of this three dimensional measurement system is illustrated by calibration results as well as applications to high precision dimensional inspection in industry.     

普通变焦数码相机快速标定方法

普通数码相机在近景摄影测量中的应用日益广泛,其标定方法备受关注。本文在传统的胶片相机标定方法的基础上,提出了一种可用于普通数码相机在焦距变化情况下的快速标定方法,并通过实验证明了该方法的可行性。     

一种非量测相机近景影像外方位元素解算方法

本文提出了一种角椎体法和共线方程法联合解算非量测相机影像外方位元素的方法。工程应用证明该方法求解像片的外方位元素具有计算速度快、收敛性强、计算精度高等优点。     

Suitability of the DCS460c colour digital camera for quantitative remote sensing analysis of vegetation

The Kodak DCS460c is a high resolution, colour digital camera with a specific CCD array mosaic structure that requires a dedicated processing algorithm for production of a three-band image. Kodak's Active Interpolation (KAI) algorithm is compared with a simpler nearest neighbour interpolation method (NNI) with regard to applicability in scientific investigations of target features in imagery. Detailed quantitative analyses of flat-field imagery were undertaken in order to provide insight into artefacts and to correct for the off nadir reduction in brightness. Characteristics of the aerial photography were also studied and aspects of processing and analysis of the imagery for scientific investigations are discussed. We present a novel method for correction of brightness fall-off (due to the vignette effects and increasing view angle) which is generally applicable to remote sensing of rural scenes. Quantitative spectral comparisons between related imagery from the DCS460c (e.g. for interpretation of relative vegetation cover) are only scientifically reliable when the raw (i.e. non-interpolated) DN values for green and red are below about 67% of their maximum range. This is due to preferential vertical leakage or charge diffusion in the CCD. A combination of CCD characteristics leads to possibly poor spatial resolution for the infrared band. The imagery after KAI shows good spatial resolution and has a natural looking colour reproduction useful for discerning features by eye. However, when using KAI, reliable spectral measurements can probably only be acquired from portions of objects that are at least four pixels from the object's boundary. In general, quantitative spatial and spectral analyses can be carried out with the DCS460c but the KAI, the broad band response and the vertical leakage require specific solutions to produce quantitative results.     

附加约束条件的DLT用于非量测数码相机的检校

从直接线性变换DLT的基本原理出发,分析了数码相机检校的DLT一般方法存在的缺陷,提出了附加约束条件的DLT相机检校方法的数学模型,并通过实验验证了其正确性和可行性.     

非量测数码相机(哈苏H1D型)在南极项目生产中的应用

简要分析了非量测数码相机哈苏H1D在南极中山站及拉斯曼丘陵地区所获取的影像数据的几何精度,阐明了利用该影像数据进行空中三角测量,DLG,DOM制作的技术流程及作业过程中出现问题的处理方法。     

无控制场的相机畸变差改正方法

本文提出并论证了一种无需控制场、仅应用影像线特征进行非量测相机畸变差测定的方法。分别运用三维室内和室外控制场、二维控制场和无控制场检校方法对Cannon-5d非量测相机的35 mm镜头进行畸变差测定,比较其影像纠正的效果。试验结果表明径向畸变在整个光学畸变中占据主要地位,四类检校方法测定的径向畸变差对影像的纠正效果接近,从而证明了利用无控制场相机畸变差改正方法进行非量测相机畸变差改正的可行性。     

Metric Exploitation of still Video Imagery

The development of still video CCD cameras with digital image storage has made feasible the concept of offline, single sensor vision metrology. This paper reports on practical evaluations of such a system for dimensional inspection of aircraft tooling and for structural monitoring for large scale engineering. A further application of still video technology for low altitude aerial mapping is also reported. In each case a Kodak DCS200 camera has been employed for the photography in order to take advantage of the relatively high sensor resolution and adequate on-board image storage capacity. Aspects of the measurement operations, which yielded object space accuracies to 1:80 000 in the industrial measurement projects, are discussed and the results analysed.     

Using a Combination of Digital Aerial Photography and Satellite Remote Sensing to Assist Contemporary Restructuring in an Urban Area of South Africa

Abstract

The transition and restructuring process of urban South Africa are currently in the phase of identifying land development objectives. These objectives aim to integrate previously segregated areas through integrated development plans. This research aims firstly to identify and describe the historical development of the spatial form and structure of the secondary city and capital of the Northern Province, Pietersburg and its dispersed peripheral towns. Supervised classification of SPOT HRV multispectral imagery is used to support the theoretical explanation. Images from an airborne digital Kodak DCS 420 camera are used to provide training sites in the pre‐classification stages, and also provide field data to the process of post‐classification accuracy assessment. Secondly, SPOT HRV imagery is applied to identify the stark contrast in urban development between the city of Pietersburg and its surrounding former homeland towns. Both built and natural environmental aspects are investigated. In conclusion benefits and problems of assessing urban morphology and development in a developing country by means of a combination of satellite imagery and digital aerial photography are discussed.